In week-long hearings set to begin Monday in San Francisco, U.S. District Judge Vince Chhabria will hear from experts about whether there is scientific evidence to support the claims of more than 300 lawsuits that exposure to Roundup can cause non-Hodgkin's lymphoma, the Associated Press reported.

The lawsuits by cancer victims and their families were filed against Roundup maker Monsanto, Co., and allege that the company knew about the product's cancer risk but did not warn consumers.

At the hearing, Chharbria will decide whether to allow the plaintiffs' medical and scientific experts to testify to a jury that Roundup can cause cancer.

Glyphosate, the active ingredient in Roundup, was developed by Monsanto in the 1970s. The weed killer is sold in more than 160 countries and is used by farmers in their fields and by homeowners on their lawns and gardens, the AP reported.

Monsanto also sells genetically modified seeds for crops that can tolerate being sprayed with glyphosate while surrounding weeds are killed.

In 2015, the International Agency for Research on Cancer -- part of the World Health Organization -- classified glyphosate as a "probable human carcinogen." California has added glyphosate to its list of chemicals known to cause cancer, the AP reported.

Monsanto says hundreds of studies have concluded that glyphosate is safe.